diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..7edc03e
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module golang.org/x/arch
+
+go 1.11
+
+require rsc.io/pdf v0.1.1
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..e854d25
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+rsc.io/pdf v0.1.1 h1:k1MczvYDUvJBe93bYd7wrZLLUEcLZAuF824/I4e5Xr4=
+rsc.io/pdf v0.1.1/go.mod h1:n8OzWcQ6Sp37PL01nO98y4iUCRdTGarVfzxY20ICaU4=